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STM32F031x4 STM32F031x6
Functional overview
23
The RTC clock sources can be:
A 32.768 kHz external crystal
A resonator or oscillator
The internal low-power RC oscillator (typical frequency of 40 kHz)
The high-speed external clock divided by 32
3.13 Inter-integrated
circuit interfaces (I
2
C)
The I
2
C interface (I2C1) can operate in multimaster or slave modes. It can support Standard
mode (up to 100 kbit/s), Fast mode (up to 400 kbit/s) and Fast Mode Plus (up to 1 Mbit/s)
with 20 mA output drive.
It supports 7-bit and 10-bit addressing modes, multiple 7-bit slave addresses (two
addresses, one with configurable mask). It also includes programmable analog and digital
noise filters.
In addition, I2C1 provides hardware support for SMBUS 2.0 and PMBUS 1.1: ARP
capability, Host notify protocol, hardware CRC (PEC) generation/verification, timeouts
verifications and ALERT protocol management. I2C1 also has a clock domain independent
from the CPU clock, allowing the I2C1 to wake up the MCU from Stop mode on address
match.
The I2C interface can be served by the DMA controller.
Table 6. Comparison of I2C analog and digital filters
Analog filter
Digital filter
Pulse width of
suppressed spikes
50 ns
Programmable length from 1 to 15
I2C peripheral clocks
Benefits
Available in Stop mode
1. Extra filtering capability vs.
standard requirements.
2. Stable length
Drawbacks
Variations depending on
temperature, voltage, process
Wakeup from Stop on address
match is not available when digital
filter is enabled.
Table 7. STM32F031x4/x6 I
2
C implementation
I2C features
(1)
I2C1
7-bit addressing mode
X
10-bit addressing mode
X
Standard mode (up to 100 kbit/s)
X
Fast mode (up to 400 kbit/s)
X
Fast Mode Plus with
output drive I/Os (up to 1 Mbit/s)
X
Independent clock
X
SMBus
X
Wakeup from STOP
X
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微可Vicor——值得信赖的元器件供应商
http://www.vicor.top/
021-31660491
